Well, Clint did make Space Cowboys, so yeah.
I would argue that
Space Cowboys is actually an underrated film, a dexterous and seamless blend of homage and parody that perhaps only Eastwood could have pulled off. Take another look at it sometime.
As for the question, to me, we're talking about apples and oranges—Kubrick and Eastwood are extremely different filmmakers. If I were to attempt a serious analysis, I would suggest that Kubrick is more significant in terms of advancing the cinematic medium's possibilities and adopting abstract approaches to genre. In a sense, he is cinema's Picasso. Eastwood, however, has made films that seem more personal, more intimate, and more realistically harrowing in their approach to violence.
Perhaps one could debate which ghost story is more compelling, Eastwood's
High Plains Drifter (1973) or Kubrick's
The Shining (1980).
Undoubtedly, though, Eastwood constituted the easier director to work for. Reportedly, Kubrick put actor Scatman Crothers through fifty takes of a scene on
The Shining. Crothers' next film was Eastwood's
Bronco Billy, released the same year. Fearful after his experience with Kubrick, Crothers wondered whether Eastwood would place him through a similar wringer. When Eastwood printed the first take, Crothers nearly cried.